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Gassy sediments and large, buried and actual seafloor pockmarks are identified on seismic records in the continental slope of the Gulf of Cadiz. The different acoustic responses produced by the gas in the sediment result from the local dynamic of the Mediterranean Undercurrent, which also controls the lithology of the slope sediments. The seafloor areas swept by this strong current are covered by coarse sediments with high porosity, which favours the escape of the gas, and then the development of pockmarks. Contrasting, the areas affected by weaker currents are covered by finer sediments of low porosity, and then the gas remains trapped into the sediment pores

Swath bathymetry and geophysical data of the island of Hierro show that the western flank of the island is affected, at least, by two major catastrophic slope failures. One of the two, called the El Golfo debris avalanche, led to the deposition of a sedimentary body of about 150 km3 of volcanic rock debris on the upper rise. The second major instability event, named the Canary debris flow, originated at the base-of-slope of the island of Hierro, and involved a larger amount of remobilized material. New evidences suggest that the Canary debris flow is the oldest in age. As a consequence of the Canary slide event, oversteeping and undermining of the lower island flanks occurred and subsequently triggered the El Golfo debris avalanche, whose deposits covered and obliterated the source area of the Canary debris flow. The triggering of El Colfo debris avalanche seems to be related also to the rift zones in the island of Hierro. From the establishment of the complex relationships between both slides, the El Golfo debris avalanche has been dated between 12.000 and 6.000 yBP Nuevos datos de batimetría y geofísica marinas de la isla de Hierro demuestran que el flanco occidental de la isla está afectado por un deslizamiento que depositó 150 km3 de derrubios volcánicos en el glacis c o n tin e n ta l superior, la avalancha de El Colfo. Un segundo evento, llam ado "debris f lo w " de Canarias, se originó en la base del talud de la isla del Hierro y movilizó unos 400 km3 de material. Nuevas evidencias sugieren que el "debris f l o w " de Canarias precedió a la avalancha de El C olfo. La avalancha de El Colfo pudo haberse originado a consecuencia de la socavación y sobreinclinación del talud asociadas a la cicatriz del «debris flow» de Canarias. Las zonas de rift en la isla del Hierro parecen haber tenido también un papel significativo en el desencadenamiento de la avalancha de El Colfo. El resultado fue el enmascaramiento del área fue nte del "debris f l o w " de Canarias p o r los depósitos de la avalancha. De la determinación de las complejas relaciones entre ambos flujos, se desprende que la avalancha de El Golfo ocurrió entre 12.000 y 6.000 años BP

A comprehensive data set of the seafloor relief and superficial sedimentary cover on the Ebro progradational continental slope, NW Mediterranean Sea, reveals that its Late Quaternary building results from complex interrelationships between processes ranging from channel abandonment to incision of inner minor courses, from retrogressive erosion and channel capture to levee cutting and new channel opening, from channel wall sliding to shelf-edge and channel spillover. These processes succeed ones to the others both in time and space conforming a canibalistic frame where the balance between destructive and constructive processes is finally favourable to the last. They result in the formation of the channel-levee complexes characteristic of the Ebro continental slope and base-of-slope

El análisis micropaleontológico de los últimos 140 000 años registrados en testigo de gravedad CAMEL-1 (5-6'25S/21-2'36W), sugirió valores bajos en la paleoproductividad de las aguas superficiales circundantes. Por otro lado, el registro de diatomeas de agua dulce y fitolitos en sedimentos marinos reflejaron incrementos en la aridez en el Continente africano durante los estadios glaciales, indicando desecación de lagos y desplazamientos del cinturón herbáceo. La combinación de los registros marinos y continentales permitió estimar la intensidad de los vientos

Physical properties measured on cores from d rill Sites o f O D P Leg 157 reveal th a t the d iffe re n t turbidites of Madeira Abyssal Plain have a distinct physical signal. Major differences result from the compositional variations among the three main types of turbidites (volcanic, organic-rich, and calcareous), and from changes in the carbonate content in the pelagic Intervals Las propiedades físicas medidas en los testigos recuperados de los sondeos del Leg 157 de ODP revelan que las diferentes turbiditas existentes en la Llanura Abisal de Madeira presentan una señal física característica. Las principales diferencias resultan de las variaciones composicionales entre los tres tipos principales de turbiditas (volcánicas, orgánicas y calcáreas), así como por cambios en el contenido en carbonato en l o s intervalos pelágicos

A peripheral depression with a sediment drift on its N flank develop N and E of Minorca Island. Both are interpreted to result from the activity of bottom currents circulating parallel to the base of the island slope since the Pliocene. Evidences of the contouriric activity are: the presence of a depression with an erosive character, a sedimentary ridge with the typical characteristics of contourite drifts, and large sediment waves. The depression has a maximum width of 5 km, and a depth of 150-200 m, whereas the contourite drift reaches up to 150 km in length, is 25 km wide, and 100 m high. The sediment waves developed on the inner flank of the contourite drift reach up to 5 km in length and 40 m in height. The genesis of all these structures is related to the circulation of the Mediterranean Deep Water ( MDW) in the area. The steep island slope, devoided of sediment and deeply gullied, is considered as the potential source area for the sediments reworked by the currents. Further seaward, the contourite deposits are in lateral continuity with the deposits of the North-Balearic Basin and the Valencia Fan

A comprehensive data set of the seafloor relief and superficial sedimentary cover on the Ebro progradational continental slope, NW Mediterranean Sea, reveals that its Late Quaternary building results from complex interrelationships between processes ranging from channel abandonment to incision of inner minor courses, from retrogressive erosion and channel capture to levee cutting and new channel opening, from channel wall sliding to shelf-edge and channel spillover. These processes succeed ones to the others both in time and space conforming a canibalistic frame where the balance between destructive and constructive processes is finally favourable to the last. They result in the formation of the channel-levee complexes characteristic of the Ebro continental slope and base-of-slope

Gassy sediments and large, buried and actual seafloor pockmarks are identified on seismic records in the continental slope of the Gulf of Cadiz. The different acoustic responses produced by the gas in the sediment result from the local dynamic of the Mediterranean Undercurrent, which also controls the lithology of the slope sediments. The seafloor areas swept by this strong current are covered by coarse sediments with high porosity, which favours the escape of the gas, and then the development of pockmarks. Contrasting, the areas affected by weaker currents are covered by finer sediments of low porosity, and then the gas remains trapped into the sediment pores

Physical properties measured on cores from d rill Sites o f O D P Leg 157 reveal th a t the d iffe re n t turbidites of Madeira Abyssal Plain have a distinct physical signal. Major differences result from the compositional variations among the three main types of turbidites (volcanic, organic-rich, and calcareous), and from changes in the carbonate content in the pelagic Intervals, Las propiedades físicas medidas en los testigos recuperados de los sondeos del Leg 157 de ODP revelan que las diferentes turbiditas existentes en la Llanura Abisal de Madeira presentan una señal física característica. Las principales diferencias resultan de las variaciones composicionales entre los tres tipos principales de turbiditas (volcánicas, orgánicas y calcáreas), así como por cambios en el contenido en carbonato en l o s intervalos pelágicos

A peripheral depression with a sediment drift on its N flank develop N and E of Minorca Island. Both are interpreted to result from the activity of bottom currents circulating parallel to the base of the island slope since the Pliocene. Evidences of the contouriric activity are: the presence of a depression with an erosive character, a sedimentary ridge with the typical characteristics of contourite drifts, and large sediment waves. The depression has a maximum width of 5 km, and a depth of 150-200 m, whereas the contourite drift reaches up to 150 km in length, is 25 km wide, and 100 m high. The sediment waves developed on the inner flank of the contourite drift reach up to 5 km in length and 40 m in height. The genesis of all these structures is related to the circulation of the Mediterranean Deep Water ( MDW) in the area. The steep island slope, devoided of sediment and deeply gullied, is considered as the potential source area for the sediments reworked by the currents. Further seaward, the contourite deposits are in lateral continuity with the deposits of the North-Balearic Basin and the Valencia Fan

El análisis micropaleontológico de los últimos 140 000 años registrados en testigo de gravedad CAMEL-1 (5-6'25S/21-2'36W), sugirió valores bajos en la paleoproductividad de las aguas superficiales circundantes. Por otro lado, el registro de diatomeas de agua dulce y fitolitos en sedimentos marinos reflejaron incrementos en la aridez en el Continente africano durante los estadios glaciales, indicando desecación de lagos y desplazamientos del cinturón herbáceo. La combinación de los registros marinos y continentales permitió estimar la intensidad de los vientos

Swath bathymetry and geophysical data of the island of Hierro show that the western flank of the island is affected, at least, by two major catastrophic slope failures. One of the two, called the El Golfo debris avalanche, led to the deposition of a sedimentary body of about 150 km3 of volcanic rock debris on the upper rise. The second major instability event, named the Canary debris flow, originated at the base-of-slope of the island of Hierro, and involved a larger amount of remobilized material. New evidences suggest that the Canary debris flow is the oldest in age. As a consequence of the Canary slide event, oversteeping and undermining of the lower island flanks occurred and subsequently triggered the El Golfo debris avalanche, whose deposits covered and obliterated the source area of the Canary debris flow. The triggering of El Colfo debris avalanche seems to be related also to the rift zones in the island of Hierro. From the establishment of the complex relationships between both slides, the El Golfo debris avalanche has been dated between 12.000 and 6.000 yBP, Nuevos datos de batimetría y geofísica marinas de la isla de Hierro demuestran que el flanco occidental de la isla está afectado por un deslizamiento que depositó 150 km3 de derrubios volcánicos en el glacis c o n tin e n ta l superior, la avalancha de El Colfo. Un segundo evento, llam ado "debris f lo w " de Canarias, se originó en la base del talud de la isla del Hierro y movilizó unos 400 km3 de material. Nuevas evidencias sugieren que el "debris f l o w " de Canarias precedió a la avalancha de El C olfo. La avalancha de El Colfo pudo haberse originado a consecuencia de la socavación y sobreinclinación del talud asociadas a la cicatriz del «debris flow» de Canarias. Las zonas de rift en la isla del Hierro parecen haber tenido también un papel significativo en el desencadenamiento de la avalancha de El Colfo. El resultado fue el enmascaramiento del área fue nte del "debris f l o w " de Canarias p o r los depósitos de la avalancha. De la determinación de las complejas relaciones entre ambos flujos, se desprende que la avalancha de El Golfo ocurrió entre 12.000 y 6.000 años BP

The GEBRA '93 (Geological Evolution of the Bransfield Basin) survey was carried out in December 1993 in the Bransfield Strait (NW Antarctic Peninsula) and adjacent areas, onboard BIO Hespérides. The geophysical data acquired allow to characterize the morphostructure, sediment cover and magnetic anomalies of the SW-NE trending Central Bransfield Basin. Some transverse shifts and tresholds, together with alongbasin volcanic alignments, complicate the morphology and seismic structure of what otherwise would have been a long, continuous axial trough opened on a crust under extension. A major submarine valley, named Gebra Valley has also been identified

The GEBRA '93 (Geological Evolution of the Bransfield Basin) survey was carried out in December 1993 in the Bransfield Strait (NW Antarctic Peninsula) and adjacent areas, onboard BIO Hespérides. The geophysical data acquired allow to characterize the morphostructure, sediment cover and magnetic anomalies of the SW-NE trending Central Bransfield Basin. Some transverse shifts and tresholds, together with alongbasin volcanic alignments, complicate the morphology and seismic structure of what otherwise would have been a long, continuous axial trough opened on a crust under extension. A major submarine valley, named Gebra Valley has also been identified